The present invention relates generally to the field of avionics and surveillance transceiver systems. More particularly, the invention relates to a method, apparatus, system, and computer software product for receiving and translating ADS-B messages from Mode S format to UAT format for broadcast using a Universal Access Transceiver.
Historically, the air traffic control system has relied upon a network of ground-based radar stations and a transponder onboard each aircraft. In response to a radar beacon interrogation from a ground station, the transponder broadcasts a response. The transponder signal provides the air traffic controller with very basic information about the aircraft. The transponder transmits a four-digit octal code and the ownship altitude. The aircraft position is inferred by measuring the time of reception and the angular position of the radar dish.
The Mode Select Beacon (Mode S) system was developed to add a unique identifier called an ICAO aircraft address to the radar beacon interrogation and to the transponder""s responsive signal. ICAO is the International Civil Aviation Organization, a body that promulgates standards for civil aviation. Because a Mode S interrogation is addressed to a specific aircraft, only the Mode S transponder onboard that particular aircraft will respond. The Mode S system is sometimes called the Mode S datalink.
The Automatic Dependent Surveillancexe2x80x94Broadcast (ADS-B) system was developed to take advantage of the satellite-based Global Positioning System (GPS) to directly transmit aircraft latitude and longitude without using ground-based radar interrogations. The GPS-based position data is updated continuously, is highly accurate, and does not require the typical transponder interrogation. An aircraft equipped with ADS-B automatically and periodically broadcasts a digital signal to all other ADS-B-equipped aircraft. The ADS-B signal contains extensive information about the aircraft""s position and heading as well as the integrity of such information.
The Federal Aviation Administration initiated the Capstone Program, a project designed to improve civil aviation safety and efficiency through the use of GPS-based avionics and datalink communications. Under the Capstone Program, certain commercial and government aircraft in the Alaska testing region were equipped with ADS-B systems. A network of ground-based transceivers capable of receiving and transmitting ADS-B signals were also installed in the testing region.
Ground-based and mobile transceivers with internal signal processors are used to receive and transmit ADS-B signals. A transceiver is capable of both receiving and transmitting signals. The Universal Access Transceiver (UAT) is a radio datalink system that supports ADS-B and other broadcast services. The UAT datalink provides communication between ADS-B-equipped aircraft and ground stations.
In addition to receiving and transmitting ADS-B signals from aircraft, the UAT datalink system is capable of uplinking and broadcasting data from fixed ground radar stations in two modes: FIS-B (Flight Information Servicesxe2x80x94Broadcast) mode and TIS-B (Traffic Information Servicesxe2x80x94Broadcast) mode. FIS-B data includes a wide variety of information, including weather broadcasts (graphical and text), airport status reports, temporary airspace restrictions, and official Notices to Airmen called NOTAMs. TIS-B data includes information about air traffic gathered from ground-based radar systems.
The RTCA, an organization that promulgates consensus-based aviation standards, is developing a standard format for messages transmitted via a UAT datalink system. This UAT format requires the data to be in a certain order. An ADS-B signal can be broadcast on a UAT datalink system if the signal is placed in the standard UAT format.
An ADS-B signal can also be broadcast on a Mode S datalink. The ADS-B signal from a Mode S datalink is called a Mode S extended squitter. The UAT datalink, however, is not equipped to receive or transmit Mode S extended squitters.
While many small planes and commuter jets are equipped with radar transponders, they are not equipped to broadcast Mode S extended squitters. Similarly, while most commercial airliners are equipped with Mode S transponders, most are not equipped to broadcast signals in UAT format. Accordingly, a mixture of equipment onboard different aircraft will remain a challenge for air traffic control and monitoring systems.
Thus, there is a need for a transceiver system that is capable of receiving a Mode S extended squitter and transmitting the data contained within the squitter in UAT format to ADS-B-equipped aircraft, vehicles, and stations. There is a related need for computer software to translate a Mode S extended squitter into a transmittable UAT-format ADS-B signal.
There is also a need for a device that will facilitate interoperability between and among the various types of avionics communication equipment in use today.
There is a further need for a single surveillance device capable of receiving Mode S extended squitters from aircraft and traffic data from fixed ground radar stations, and further capable of transmitting the data in an ADS-B-compatible format using a Universal Access Transceiver radio datalink system.
The above and other needs are met by the present invention which, in one embodiment, generally provides an apparatus, a method, and a system for receiving extended squitters from Mode S transponders, translating the squitters into ADS-B state vectors, and transmitting the ADS-B state vectors using a transceiver system. The transceiver system integrates transponder datalink technology and ADS-B datalink technology in a single surveillance receiver.
In one aspect of the present invention, the apparatus for processing a squitter includes a receiver capable of receiving the squitter in a first format from a vehicle, a processor configured to translate the squitter into a new transmittable ADS-B signal in a second format, and a transmitter. In one embodiment, the squitter is an extended squitter made up of several segments broadcast by a Mode S transponder. In one embodiment, the transmittable ADS-B signal is an ADS-B state vector in UAT format composed according to existing standards.
In one embodiment, the processor may include several processors connected to one another and connected to the receiver and the transmitter. The processor or processors may also be configured to control the receipt and transmission of traffic data from fixed ground radar stations.
In one embodiment, the transmitter is a transceiver, capable of receiving and transmitting signals in a second format. Where such a transceiver is present, the processor is configured to suspend translation of a squitter received from a target when a signal having the second format is also received from the same target. In one embodiment, the transmitter is a Universal Access Transceiver (UAT) and the processor suspends translation of incoming signals that are in UAT format.
In another aspect of the invention, the apparatus for translating a squitter into an ADS-B signal in UAT format includes a squitter receiver and a processor. The processor is configured to parse the squitter into its component data and then use the data to compose an ADS-B state vector. In one embodiment, the parsed data may be stored in a track file.
In another aspect, a method for processing a squitter generally includes the steps of receiving the squitter from a vehicle via a receiver, translating the squitter into a transmittable ADS-B signal using a processor, and transmitting the ADS-B signal in UAT format via a transmitter. The step of translating, in one embodiment, includes parsing the squitter into its component data and composing the new ADS-B signal using the data. In one embodiment, the step of parsing the squitter includes storing the data in track file.
In an embodiment where the transmitter is a transceiver capable of receiving and transmitting UAT signals, the method of the present invention also includes the step of suspending the translation of a squitter received from a target when an UAT signal is also received from the same target.
In another aspect, the method of translating a squitter within a transceiver system includes the steps of receiving the squitter, parsing the squitter into its component data, composing a new ADS-B signal from the data, and transmitting the ADS-B signal. The parsing and composing steps may be accomplished in one or more processors, alone or in cooperation with one another.
In another aspect of the invention, a system for processing a squitter includes a vehicle equipped with an onboard transmitter, a receiver configured to receive the squitter from the onboard transmitter, a computer processing device, and a transmitter. The computer device includes a first processing portion to parse the squitter into its component data and a second portion to compose a new ADS-B signal using the data.
In one embodiment, the system includes several computer devices that may work in tandem to execute the first and second processing portions. In one embodiment, the computer device includes a third processing portion to compose the new ADS-B signal in UAT format. In an embodiment where the transmitter is a transceiver, the computer device also includes a fourth processing portion to suspend translation of a squitter received from a target when a UAT signal is also received from said target.
In another embodiment of the system, the computer device also includes a traffic processing portion to receive traffic data from fixed ground radar stations and a broadcast processing portion to direct the transmitter to transmit said traffic data.
In another aspect, the invention includes computer software for translating a squitter into an ADS-B signal in UAT format. The software is designed to operate within a system having a transceiver component. The software includes a first executable portion to parse the squitter into its component data and a second portion to compose the ADS-B signal from the data.
In one embodiment, the first executable portion includes a sub-portion to store the data in a track file. In one embodiment where the transmitter is a transceiver, the software also includes a third executable portion to suspend translation of a squitter received from a target when a UAT signal is also received from said target.
In yet another aspect of the present invention, a squitter translator is integrated into an existing transceiver system. The squitter translator includes a squitter receiver and a squitter processor. The squitter processor is linked to the transceiver system such that the squitter in a first format is translated into an ADS-B signal in a second format suitable for broadcast by the transceiver system.
In another aspect, the present invention includes a translator module for use with an existing transceiver system. The module includes a receiver and a squitter processor. The squitter processor is designed to be connected for data communication to the transceiver system. The squitter processor translates the squitter in a first format into a new ADS-B signal in a second format that is compatible with the transceiver. In one embodiment, the squitter processor parses the squitter into its component data and then composes the ADS-B signal using the data.
Thus, it is an object of the present invention to provide an apparatus for translating Mode S extended squitters into ADS-B signals in UAT format. It is a related object of the present invention to provide a system for receiving squitters from transponders, for translating the squitters into ADS-B state vectors, and for transmitting the ADS-B state vectors in UAT format using a UAT datalink system.
It is a further object of the present invention to provide an apparatus and a transceiver system that is capable of receiving a Mode S extended squitter and transmitting the data contained within the squitter to ADS-B-equipped aircraft in a compatible format. It is a related object of the present invention to provide processors and computer software to translate the Mode S squitter into a transmittable ADS-B signal in UAT format.
It is also an object of the present invention to provide a single surveillance device capable of receiving Mode S squitters, ADS-B signals, and traffic data from fixed ground radar stations, and further capable of transmitting the data in an ADS-B-compatible format using a universal access transceiver radio datalink system. It is a related object of the present invention to facilitate interoperability between and among the various types of avionics communication equipment.
These and other objects accomplished by the present invention will become apparent from the following detailed description of one preferred embodiment in conjunction with the accompanying drawings.